Paul Kurtz’s letter inviting me to write this article suggested that I describe “my own personal involvement” in the skeptical movement. My introduction to skepticism was a fascination with a particular pseudoscience, “creation science”. From the day I first heard this phrase, I was hooked.

In 1971, I was a graduate student in physical anthropology at the University of Missouri. One day, my professor, Jim Gavan, handed me a stack of small, brightly colored, slick paper pamphlets from the Institute for Creation Research. “Here”, he said, “Take a look at these. It’s called ‘creation science.’”

Wow. Here I was studying to be a scientist, and here were people calling themselves scientists, but we sure were not seeing the world the same way. They were looking at the same data: the same fossils, the same stratigraphy, the same biological principles, and so on. But from these data, creationists were concluding that all living things had appeared in their present form, at one time, a few thousand years ago. I was concluding that living things had branched off from common ancestors over scarcely imaginable stretches of time. They were concluding that the entire planet had been covered by water, and that all the present-day geological features of earth had been determined by this flood and its aftermath. I could not see any evidence for this at all, and much evidence against it. Why were we coming up with such different conclusions? The data were not all that different, but the philosophy of science and the approach to problem solving sure were.

I began collecting “creation science” literature as an academic enterprise: an interesting problem in the philosophy of science and critical thinking. Due to the pressures of graduate school and my first teaching job, I was not able to pursue it especially deeply, but students would occasionally bring up the topic. I would tell them that even if proponents of “creation science” claimed they were doing science, one cannot claim that one is doing science if one is doing something very different from what scientists are doing. “Creation science” was a good foil to use in teaching students about the nature of science.

Philosophers of science can — and do — argue incessantly over the definition of science. I do not know how many academic papers have been written attempting to solve the “demarcation problem”: what qualifies as science and what does not. Some partisans even go so far as to claim that science is impossible to define. I confess to having little tolerance for such “how many angels can dance on the head of a pin” type discussions. In my present job as executive director of the National Center for Science Education, I regularly encounter the public’s misunderstanding of the most basic elements of science. I deal with people who nod in agreement with a typical creationist statement that “neither evolution nor creationism is scientific because no one was there to observe it”. I deal with people who agree with creation scientists stating that “evolution is not scientific because evolutionists are always changing their minds”. A very popular view is that we should “give the kids all the options” in a science classroom, and teach them both data demonstrating that evolution took place and “the evidence” for the “alternate theory” that God created everything at one time in its present form — two mutually exclusive views.

Against such a background, the philosopher’s discussion of the nuances of the demarcation problem become an intellectual luxury far removed from what people need to hear. Doubtless to the frustration of my colleagues in the philosophy of science, my job requires me to simplify — probably far beyond what they consider acceptable. But in doing so, I can make a little progress in helping the public to understand why science works, and also why “creation science” is not science. Maybe down the road the nonscientists I encounter can tackle falsificationism and the demarcation problem; right now, I would be happy if they understood two basic rules of science that I believe the majority of scientists would agree upon — however much they might disagree on others. And — more importantly for this discussion — “creation science” can be rejected as science based even on this simplest of understandings of what science is.

The nature of science
There are two basic principles of science that creationism violates. First, science is an attempt to explain the natural world in terms of natural processes, not supernatural ones. This principle is sometimes referred to as methodological naturalism. In time, a consensus of how some aspect of nature works or came about is arrived at through testing alternate explanations against the natural world. Through this process, the potential exists to arrive at a truly objective understanding of how the world works.

Please allow a digression here. I am not presenting a cut-and-dried formula — “the scientific method” — as if the process of science were a lockstep algorithm. It is much untidier than that. Of course science reflects the time and culture in which it is found. Of course scientists, being human, have biases and make mistakes. Yet the growth of knowledge in a field is not the result of individual achievement, but rather is a function of a number of minds working on the same and different problems over time. It is a collective process, rather than the result of actions of a solitary genius. Individual scientists may be biased, closed-minded, and wrong, but science as a whole lurches forward in spite of it all thanks to its built-in checks.

An important check is that explanations must be tested against the natural world. Thus there is an external standard against which a scientist’s views are measured, regardless of his biases or the biases of his opponents. Unpopular ideas may take longer to be accepted, and popular ideas may take longer to be rejected, but the bottom line determining acceptance or rejection is whether the ideas work to describe, predict, or explain the natural world. The Soviet geneticist Lysenko foisted a “Lamarckian” (inheritance of acquired characteristics) theory of heredity upon the Soviet scientific establishment because Lamarckian genetics was more politically compatible with Marxism than Mendelian genetics. His politically biased science set Soviet genetics back a full generation, but today Russians employ Mendelian genetics. Wheat raised in refrigerators does not grow any better in Siberia than regular wheat, and after a series of 5-year plans gone bust, eventually the Soviet government figured out that Lysenko had to go. “Mendelism” works; “Lysenkoism” does not.

Science is nothing if not practical. The explanations that are retained are those that work best, and the explanations that work best are ones based on material causes. Nonmaterial causes are disallowed.

The second minimal principle of science is that explanations (which is what theories are) are tentative, and may change with new data or new theory. Now, do not misunderstand me: I am not claiming that all scientific explanations always change, because in fact some do not. Nonetheless, scientists must be willing to revise explanations in light of new data or new theory. The core ideas of science tend not to change very much — they might get tinkered with around the edges — whereas the frontier ideas of science may change a lot before we feel we understand them well.

Here then are two critical strictures on modern science: science must explain using natural causes, and scientists must be willing to change their explanations when they are refuted. Viewed in the light of these two basic tenets of science, “creation science” fails miserably.

Explaining through natural cause
When a creationist says, “God did it”, we can confidently say that he is not doing science. Scientists do not allow explanations that include supernatural or mystical powers for a very important reason. To explain something scientifically requires that we test explanations against the natural world. A common denominator for testing a scientific idea is to hold constant (“control”) at least some of the variables influencing what you are trying to explain. Testing can take many forms, and although the most familiar test is the direct experiment, there exist many research designs involving indirect experimentation, or natural or statistical control of variables.

Science’s concern for testing and control rules out supernatural causation. Supporters of the “God did it” argument hold that God is omnipotent. If there are omnipotent forces in the universe, by definition, it is impossible to hold their influences constant; one cannot “control” such powers. Lacking the possibility of control of supernatural forces, scientists forgo them in explanation. Only natural explanations are used. No one yet has invented a theometer, so we will just have to muddle along with material explanations.

Another reason for restricting ourselves to natural explanations is practical. It works. We have gone a long way towards building more complete and, we think better, explanations through methodological naturalism, and most of us feel that if it ain’t broke, don’t fix it. Also, being able to say, “God (directly) did it” is a “science stopper”, in the words of philosopher Alvin Plantinga (2001). To say “God did it” means one does not need to look further for a natural explanation. For example, creationist literature abounds with criticisms of origin-of-life research. Because scientists have not yet reached a consensus on how the first replicating molecule came about, creationists argue, this is an intractable problem that should just be attributed to “God did it”. Well, if we stop looking for a natural explanation for the origin of life, surely we will never find it. So even if we have not found it yet, we must nonetheless slog on.

“Creation science”, for all its surface attempts (especially in its presentation to the general public) to claim to abide by a strictly scientific approach, relying solely on empirical data and theory, eventually falls back to violating this cardinal rule of methodological naturalism. Sometimes one has to go a bit deep in an argument, but eventually, as in the well-known Sidney Harris cartoon, “then a miracle occurs”.

For example, to a creation scientist holding to Flood Geology, Noah’s Flood was an actual historical event, and representatives of all land animals plus Noah, his wife, their sons, and their sons’ wives were on a large boat. Q: All land animals? A: Sure. The Ark is the size of the Queen Mary. Q: But there are thousands of species of beetles alone! How could all land animals be on the Ark? A: Oh, Noah did not take two of every species. He took pairs of each kind, and kinds are higher taxonomic levels than species. Q: But how could only 8 people take care of a Queen Mary-sized boat full of animals? How could they feed, water, and clean out the stalls? A: They did not have that much work, because the rocking movement of the boat caused most of the animals to estivate, or go dormant, obviating the need for feeding, watering, and stall-cleaning. Q: But the Ark floated around for almost a year before landing! Small mammals, such as mice and shrews, have a high surface–area: body–mass ratio, and have to eat almost their weight in food each day just to keep their metabolism up. These animals could not have survived estivation. A: Well, then, a miracle occurred.

Push a creationist argument far enough, and sure enough, it will become necessary to resort to a miracle. But miracle-mongering cannot be part of science.

In addition to the familiar “creation science” that got me interested in this particular pseudoscience, in the last ten years or so a newer form of anti-evolutionism has made its appearance: “Intelligent Design” (ID) creationism. ID harks back to the 1802 position of clergyman William Paley that structural complexity (such as the vertebrate eye for Paley or the structure of DNA for his latter-day bedfellows) is too complicated to have come about through a natural process. Therefore it must have been designed by an “intelligence”. The “intelligence” of course is God, and attributing natural causality to a supernatural power of course violates methodological naturalism. Recognizing that methodological naturalism is the standard of modern science, ID proponents argue that it should be scuttled, and replaced with what they call “theistic science”, which possesses the enviable ability to invoke the occasional miracle when circumstances seem to require it (Scott 1998). ID proponents are content to allow methodological naturalism for the vast amount of science that is done; they wish to leave the possibility of supernatural intervention only for those scientific problems that have theological implications, such as the Big Bang, the origin of life, the appearance of “kinds” of animals (the Cambrian Explosion), and the origin of humans. The strength of methodological naturalism is perhaps best illustrated by its general acceptance by both the ID and “creation science” wings of the anti-evolution movement — except when it comes to religiously sensitive topics.

The importance of changing your mind
So creationists violate the first cardinal rule of science, the rule of methodological naturalism, but they also violate the second cardinal rule — that of being willing to change or reject one’s explanation based on good evidence to the contrary. This is most clearly revealed by the creationist treatment of empirical data. Now, the problem is not that creationists sift through the scientific literature to find data that support the creation “model”; that in itself is not out of line. Scientists do seek confirming data (in the real world, as well as in the literature). But creationists ignore evidence that disconfirms their view, because they are not willing to change their explanations in the light of new data or theory.

Judges are not famous for their scientific acuity (witness Justice Scalia’s dissent in the 1987 Supreme Court’s Edwards v Aguillard case), but one judge got it remarkably right. William Overton, in the decision in McLean v Arkansas, wrote,

The creationists’ methods do not take data, weigh it against the opposing scientific data, and thereafter reach the conclusions stated in section 4(a).
Instead, they take the Book of Genesis and attempt to find scientific support for it.
While anybody is free to approach a scientific inquiry in any fashion they choose, they cannot properly describe the methodology used as scientific, if they start with a conclusion and refuse to change it regardless of the evidence developed during the course of the investigation.
A theory that is by its own terms dogmatic, absolutist and never subject to revision is not a scientific theory.

For decades now, creationists have claimed that the amount of meteoritic dust on the moon disproves evolution. The argument goes like this: Based on scientific measurements, the amount of meteoritic dust falling on the earth is X tons per year; a proportionate amount must also fall on the moon. If the earth and moon were ancient as evolutionists claim, then the amount of dust on the moon would be several hundreds of feet thick, since in the scant atmosphere of the moon, the dust would not burn up as it does on the earth. When astronauts landed on the moon, they found only a few inches of dust, proving that the moon is young, so the earth is young, so there is not enough time for evolution, so evolution did not happen and therefore God created the earth, moon, and everything else in the universe 10 000 years ago.

Decades ago, creationists were told that the data they use for the amount of dust falling on the earth was inaccurate. More accurate measurements of the amount of meteoritic dust influx to the earth are degrees of magnitude smaller than the original estimates cited by creationists. Before astronauts landed on the moon, satellites had accurately measured the amount of dust occurring in space, and NASA predicted that the surface of the moon would be covered by no more than a few inches of dust — exactly what astronauts found. Even though this information has been available for decades, and evolutionists time and again have pointed out flaws in the creationist argument, the dust on the moon argument still is touted as “evidence against evolution”. If this were a normal scientific theory, it would have been abandoned and forgotten long ago, an empirical stake in its heart, but this creationist zombie keeps rising again and again.

It is hard to argue that one is doing science when one can never bring oneself to abandon a refuted argument, and “creation science” is littered with such rejects. More modern forms of creationism such as “intelligent design theory” have not been around as long, and have not built up quite as long a list of refuted claims, but things do not look very good for them at this point. Michael Behe (1996) has proposed the idea that certain biochemical functions or structures are “irreducibly complex”: because all components must be present and functioning, such structures could not have come about through the incremental process of natural selection. The examples he uses in his book Darwin’s Black Box, such as the bacterial flagellum and the blood-clotting cascade, appear not to be irreducibly complex after all. Worse, even granting the theoretical possibility that an irreducibly complex structure could exist, there is no reason it could not be produced by natural selection. A (theoretically) irreducibly complex structure would not have to have all of its components assembled in its present form all at one time. The way natural selection works, it is perfectly reasonable to envision that some parts of such a structure could be assembled for one purpose, other parts for another, and the final “assembly” results in a structure that performs a function different from any of the “ancestral” functions. As complex a biochemical sequence as the Krebs cycle has recently been given an evolutionary explanation of this sort (Melandez-Hevia and others 1996).

I am willing to give “intelligent design” (ID) a little more time to demonstrate that it is, as it aspires to be, a truly scientific movement. To be able legitimately to claim that ID is scientific, however, will require that its proponents be willing to abandon ideas in the light of refuting evidence — something that their ideological ancestors, the “creation scientists”, have been unable to demonstrate, and which we have seen precious little of from the leaders of the ID movement.

Logical problems
Needless to say, in addition to violating the two key principles of science, the “science” of creationism demonstrates other weaknesses, not the least important is its logic. “Creation scientists” posit a false dichotomy of only two logical possibilities: one being special creationism as seen in a literal interpretation of Genesis, and the other being evolution. Therefore, if evolution is disproved, then creationism is proved; arguments against evolution are arguments for creationism. “Creation science” literature is largely composed of a careful sifting of legitimate scientific articles and books for anomalies that appear to “disprove” evolution.

But of course, to disprove one view is not to prove another; if I am not at home in Berkeley, that does not mean I am on the moon. Accepting the “if not A, then B” form of argument requires that there are only two possibilities. If the only two possibilities are that I am in Berkeley or on the moon, then indeed, evidence that I am not in Berkeley is evidence that I am on the moon, but clearly there are more than two alternatives as to my whereabouts. Similarly, there clearly are far more alternatives to scientific evolution than biblical creationism. There are several Hopi origin stories, several Navajo ones, scores of other Native American views, several dozen sub-Saharan African tribal explanations, and we have not even looked at South Asia, Polynesia, Australia, or views no longer held such as those of the ancient Norse and ancient Greeks. Even if evolution were disproved, biblical literalists would have to find ways of disproving all of these other religious views, so the logic fails.

More than an academic exercise
For many years, then, my interest in creationism was largely academic. It was an interesting exercise in the philosophy of science. But a few years after I left Missouri, my professor Jim Gavan unwisely accepted an invitation to debate the ICR’s Duane Gish. Gish had perfected a hugely effective technique for persuading the public that evolution was shaky science, and that folks should really consider his “scientific alternative”. I and some of my Kentucky students drove from Lexington to Missouri to attend the debate, and it was an eye-opener. I counted 13 buses from local church groups parked outside the big University of Missouri auditorium, and after seeing the enthusiasm with which the audience received Gish and his message, the cold water of the social and political reality of this movement hit me for the first time. It was no longer just an academic exercise. People were taking this pseudoscience very seriously.

The late Jim Gavan was an excellent scientist, a former president of the American Association of Physical Anthropology, a smart and articulate man well-grounded in philosophy of science. He had done his homework: he had studied creationist literature for several months and came as prepared as anyone could be expected to be. Clearly, his scientific arguments were superior, but from the perspective of who won the hearts and minds of the people, Gish mopped him up.

So I realized that there was a heck of a lot more in this creationism and evolution business than just the academic issues. I went back to Lexington and my job of teaching evolution to college students with a new appreciation of a growing movement that had as its goal the undermining of my professional discipline, to say nothing of the scientific point of view. But still — there were pressures to publish, and a high teaching load, and I was still learning my job, so I did not take an active role in the controversy quite yet.

Then in 1976, I went to the University of Kansas in Lawrence, as a visiting professor. As I walked across campus one day, I saw a poster advertising a debate between two professors, Edward Wiley and Pat Bickford with Duane Gish and Henry Morris from the ICR. My first thought was, Do these guys know what they are getting in for? I jotted down the names of the professors and called up Ed Wiley. I told him that I had a collection of creationist materials that I was happy to make available to him, and offered to discuss the upcoming debate with him some time. We met and shared resources, and because of Ed’s strategy I began to think that maybe this debate would be different.

Gish’s usual stock in trade was to attack Darwinian gradualism because virtually all of his evolutionist opponents defended it. Ed Wiley had recently arrived from the American Museum of Natural History, where he had been converted to some new approaches to evolutionary biology that Gish had not heard of yet. Whereas Gish anticipated that his opponent would defend Darwinian gradualism, Ed merely sniffed that Dr Gish had not kept up on the latest scholarship and went on to explain punctuated equilibria and cladistics. Worse for Gish, not only did Wiley ignore Darwinian gradualism, he almost ignored evolution completely, concentrating instead on attacking “creation science” as being a nonscience, and as being empirically false.

This debate was a disaster for the creationism side. Gish did not know what to say: his target had disappeared, and he was faced with new information with which he was totally unfamiliar (needless to say, by his next debate, he had figured out a “refutation” of punctuated equilibria, and no other evolutionist opponent would ever catch him unprepared on this topic). It was pleasant to behold, especially after having seen my mentor and friend Jim Gavan skunked by Gish a couple of years before.

But the most memorable moment in the debate did not have anything to do with science. Geologist Pat Bickford was paired with the avuncular founder of creation science, Henry M Morris, and did a good job showing the scientific flaws of Morris’s “flood geology model” (according to which all the world’s important geological features were formed by Noah’s Flood), although I do not know how many in the audience understood much of his technical presentation. As with the Gavan/Gish debate, the audience was dominated by people who had arrived on buses from regional churches, and they were there to cheer their champions Gish and Morris. I was sitting behind a young girl of 11 or so and her mother.

Bickford began his presentation by pointing out that he was an active churchgoer, had been one for many years, and found this not at all incompatible with his acceptance of evolution. The girl in front of me whirled to face her mother and said, “But you told me —” and her mother, equally shocked and intent on hearing more, said, “Shhhhhhhh!” They had come to the debate convinced that one had to choose between evolution and religion. Bickford’s testimonial exposed them to empirical evidence that this was not true. I suspect that they wondered what else they had been told that was not true. I noticed that they listened to Bickford far more intently than they had listened to Wiley and left with a thoughtful look in their eyes.

But my true baptism into realizing the depth and extent of the social and political importance of the “creation science” movement came in 1980 in Lexington, Kentucky, when the “Citizens for Balanced Teaching of Origins” approached the Lexington school board to request that “creation science” be introduced into the curriculum. Because I had a collection of creationist literature collected over the years, I became a focal point for the opposition to this effort. After over a year of controversy, our coalition of scientists and liberal and moderate clergy (who objected to biblical literalism being presented in the public schools) managed to persuade the Lexington Board of Education to reject the proposal — by a scant 3–2 margin.

Creationism and Pseudoscience
What happened in Lexington has happened in community after community across the United States, although the evolution side has not always prevailed. I learned from the Lexington controversy (and from observing creation/evolution debates) that “creation science” is not a problem that will be solved merely by throwing science at it. And I suspect that this is generally also the case with other pseudosciences. Like other pseudosciences, “creation science” seeks support and adherents by claiming the mantle of science. Proponents argue that “creation science” should be taught in science class because it supposedly is a legitimate science. This point must be refuted, and scientists are the best ones to make the point. But showing that creationism is unscientific (and just plain factually wrong) is insufficient, however necessary. People who support “creation science” do so for emotional reasons, and are reluctant or unwilling to relinquish their belief unless those needs or concerns are otherwise assuaged. I suspect the same thing can be said for believers in UFOs, or out-of-body experiences, or paranormal phenomena in general: these beliefs are meeting some emotional needs, and consequently will be very difficult to abandon.

In the case of creation science, the needs being met are among those associated with religion, which makes the adherence to creationism particularly difficult to give up. Creationism is most closely associated with a particular theology of special creationism; not all religion is inimical to evolution, as demonstrated both by scientists who are religious and religious non-scientists who accept evolution. But if your theology requires you to interpret your sacred documents in a literal fashion (whether the Bible, the Torah, the Koran, or the Vedas), in most cases, evolution will be difficult to accommodate with faith.

Some anti-evolutionists — most of the ID supporters, for example — think that evolution is incompatible with faith not because their theology is biblically literalist, but because they believe that a God who works through evolution is too remote; their theology requires a very personal God who is actively involved with individual human lives and who therefore gives purpose and meaning to life. The God of the theistic evolutionist, the one who uses evolution to construct living things much as Newton’s God used gravitation to construct the solar system, is too distant; evolution to them is a step down the slippery slope toward deism.

But whether in the form of biblical literalism or not, religious sensibilities are the engine driving anti-evolutionism. Religion is a powerful force in human lives. If religion did not meet many human needs, it would not be a cultural universal; obviously we are dealing with many complex psychological issues. No matter how sound Jim Gavan’s science was during his debate with Gish, he failed to move most of his listeners because they came to the debate convinced that evolution was fundamentally incompatible with their religion. Pat Bickford’s casual mention that he was a churchgoer was critical to the success of the Kansas debate, because it forced audience members to grapple with a new idea: that one could be an evolutionist and also a Christian. In Lexington, scientists could point out that “creation science” was not science, but the clergy could assuage the public’s emotional concerns that by “believing” in evolution, they were giving up something important to them. Scientists alone could not have won the day. If 95 clergymen had not signed a petition stating that evolution was fine with them and that they felt that the schools should not be presenting a religious doctrine as science, community sentiment would not have allowed the board of education to make the decision it did.

Those of us concerned about pseudoscience and its attractiveness to the public would be well advised to consider the emotional needs that are met by beliefs in ESP, alien abduction, astrology, psychic powers, and the like, and address them as well as criticizing the poor science invoked by supporters to support the pseudoscience. We skeptics sometimes feel that the people we are trying to reach are impenetrable — and some of them are! The public is divided into 3 parts: confirmed believers, confirmed skeptics, and a much larger middle group that does not know much science, but does not have the emotional commitments that might lead it to embrace a pseudoscientific view. In the case of creation science, the emotional commitment (among many) is to the particular theology of biblical literalism; in the case of UFO abductees, it may be a need for a quasi-religious benevolent protector (or conversely, the fear of an omnipresent threat against which one is powerless). I have found that I am most effective with that large middle group, and hardly ever effective with the true believers; I suspect most skeptics have had similar experiences.

But after all, reaching that large middle group is also the goal of the proponents of pseudoscience. If, like most skeptics, you feel that we would all be better off with more science and less pseudoscience, then that is where we should be focusing our energies, rather than fruitlessly arguing with people who will never agree with us. But to reach that group that is potentially reachable, we must also be aware that a scientific explanation is necessary but not sufficient to change someone’s mind; if I have learned anything from over 25 years in the skeptic business, it is that it is necessary to deal with the emotional reasons that make our species susceptible to these beliefs, as well as the scientific.